I own two cheap pedestal fans - Big W $20 type - I've owned them for six or more years and they get a fair bit of use in summer as my house does not have air conditioning. They have done a fine job without issues for those years.
They had both become a little dirty on the fan blades and the areas where the wires are close near the centre of the fan guard, it must be three years since I cleaned them.
I took one fan apart, brushed the dirt from the guard and washed the propeller in warm soapy water, reassembled and all was good the fan was doing it's job.
That evening I checked fan number two and noticed that it wasn't as dirty as number one but seemed very inefficient in that at one metre distant I could not feel air flow from the fan. The next morning I checked number one and could easily feel airflow at three metres.
I did a strip and clean on number two, reassembled, and could now feel airflow at three metres and more.
What I'm guessing is happening: The fan propeller has three blades and each has a very sharp leading edge, if you tried really hard it would cut your finger, and I suspect that as dirt build up on the leading edge and blunts it then instead of slicing through the air the blunter edge is causing turbulence and preventing the blades getting hold of a solid column of air to push forwards.
So... if you're no longer a fan of your fan a good wash and brush up may give it a new lease of life.
MH
aussie_paul said
06:56 PM Mar 19, 2017
Aussie Paul.
Happywanderer said
07:12 PM Mar 19, 2017
I've got 4 different fans, all with dirty blades.
One I managed to pull apart and clean last year. Must do all the fans. Wish there was an easier way.
diggerop said
07:51 PM Mar 19, 2017
Fan blades do not need a sharp leading edge, same as aeroplane propellors and also their wings and helicopter blades. Trailing edges are sharper than leading edges. It would be just the dust and fluff not being very slippery slowing the airflow down.
Aussie said
07:54 PM Mar 19, 2017
Happywanderer, there is an easier way, buy a new fan from Woolies for $15 and sell the old one at a garage sale for $10, no sweat.
Craig1 said
08:03 PM Mar 19, 2017
I bet REX Airlines wish they had thought of that one
Mike Harding said
08:27 PM Mar 19, 2017
diggerop wrote:
Fan blades do not need a sharp leading edge, same as aeroplane propellors and also their wings and helicopter blades. Trailing edges are sharper than leading edges. It would be just the dust and fluff not being very slippery slowing the airflow down.
I know nothing of fluid mechanics so my theory is very possibly incorrect.
But in regard to your comparison of fans and aircraft propellers... they need to push air in opposite directions I think - fans push it forward and aircraft push it backwards...?
Happywanderer said
09:17 PM Mar 19, 2017
Aussie wrote:
Happywanderer, there is an easier way, buy a new fan from Woolies for $15 and sell the old one at a garage sale for $10, no sweat.
Good idea, except, they are all 12 volt and doubt I would find them at Woolies. They were all more expensive than $15. One bought at a camping show.
When back on the road next week, I will get the screwdriver out.
meetoo said
10:05 PM Mar 19, 2017
Mike Harding wrote:
diggerop wrote:
Fan blades do not need a sharp leading edge, same as aeroplane propellors and also their wings and helicopter blades. Trailing edges are sharper than leading edges. It would be just the dust and fluff not being very slippery slowing the airflow down.
I know nothing of fluid mechanics so my theory is very possibly incorrect.
But in regard to your comparison of fans and aircraft propellers... they need to push air in opposite directions I think - fans push it forward and aircraft push it backwards...?
Just stand on the other side.
Lancelot Link said
12:06 AM Mar 20, 2017
Oh dear, as always, my next comment is going to cause problems, why don't you just buy an air conditioner?
Bagmaker said
08:09 AM Mar 20, 2017
diggerop wrote:
Fan blades do not need a sharp leading edge, same as aeroplane propellors and also their wings and helicopter blades. Trailing edges are sharper than leading edges. It would be just the dust and fluff not being very slippery slowing the airflow down.
Yes they do Diggerop, the sharper the better.
Aircraft size airscrews have issues with bugs, fatigue strength and icing, they are designed heavily toward the safety side of airflow, not efficiency.
Same as a boat propellor, your average tinny prop is quite blunt but a racing prop is very sharp and disturbingly thin-walled.
hako said
08:48 AM Mar 20, 2017
I've found that another reason the cheap fans slow with age is that the bearings at the front and rear of the motor start to run low on lubrication so when we annually clean the fan blades we apply a drop or two to the bearings. Bunnings had the fans for $10.40 the other day so we bought 4 of them to pack away for next year so we can dump the old ones as one of the fan blades has lost it's flexibility and is splitting. ...planned obsolescence!
Good Luck.
Happywanderer said
12:14 PM Mar 20, 2017
Lancelot Link wrote:
Oh dear, as always, my next comment is going to cause problems, why don't you just buy an air conditioner?
What's that? A bit like an iron? Never heard of either.
Aussie said
02:22 PM Mar 20, 2017
Happywanderer, An air conditioner is a device that makes for pleasant living after a rushed Sunday night dinner of Baked Beans.
Happywanderer said
03:01 PM Mar 20, 2017
Aussie wrote:
Happywanderer, An air conditioner is a device that makes for pleasant living after a rushed Sunday night dinner of Baked Beans.
Oh that's why I've never heard of it. I don't eat baked beans.
Bruce and Bev said
08:09 PM Mar 22, 2017
its amazing how many people don't clean the air filters (or the plastic direction vanes in their RV or home air cons.
Next time to make a social visit into someone elses RV - have a discreet look - of course all of us reading this clean these items regularly lol
A 10 minute job under and tap and sometimes a soft hearth brush on the filters and a wipe with a rag of the vanes.
Amazing how your air con suddenly works so much better..........
I own two cheap pedestal fans - Big W $20 type - I've owned them for
six or more years and they get a fair bit of use in summer as my
house does not have air conditioning. They have done a fine job
without issues for those years.
They had both become a little dirty on the fan blades and the areas
where the wires are close near the centre of the fan guard, it must
be three years since I cleaned them.
I took one fan apart, brushed the dirt from the guard and washed the
propeller in warm soapy water, reassembled and all was good the fan
was doing it's job.
That evening I checked fan number two and noticed that it wasn't as
dirty as number one but seemed very inefficient in that at one metre
distant I could not feel air flow from the fan. The next morning I
checked number one and could easily feel airflow at three metres.
I did a strip and clean on number two, reassembled, and could now
feel airflow at three metres and more.
What I'm guessing is happening:
The fan propeller has three blades and each has a very sharp leading
edge, if you tried really hard it would cut your finger, and I
suspect that as dirt build up on the leading edge and blunts it then
instead of slicing through the air the blunter edge is causing
turbulence and preventing the blades getting hold of a solid column
of air to push forwards.
So... if you're no longer a fan of your fan a good wash and brush up
may give it a new lease of life.
MH
Aussie Paul.
One I managed to pull apart and clean last year. Must do all the fans. Wish there was an easier way.
I know nothing of fluid mechanics so my theory is very possibly incorrect.
But in regard to your comparison of fans and aircraft propellers... they need to push air in opposite directions I think - fans push it forward and aircraft push it backwards...?
Good idea, except, they are all 12 volt and doubt I would find them at Woolies. They were all more expensive than $15. One bought at a camping show.
When back on the road next week, I will get the screwdriver out.
Just stand on the other side.
Yes they do Diggerop, the sharper the better.
Aircraft size airscrews have issues with bugs, fatigue strength and icing, they are designed heavily toward the safety side of airflow, not efficiency.
Same as a boat propellor, your average tinny prop is quite blunt but a racing prop is very sharp and disturbingly thin-walled.
Good Luck.
What's that? A bit like an iron? Never heard of either.
Oh that's why I've never heard of it. I don't eat baked beans.
Next time to make a social visit into someone elses RV - have a discreet look - of course all of us reading this clean these items regularly lol
A 10 minute job under and tap and sometimes a soft hearth brush on the filters and a wipe with a rag of the vanes.
Amazing how your air con suddenly works so much better..........